> ## Documentation Index > Fetch the complete documentation index at: https://docs.uselotus.io/llms.txt > Use this file to discover all available pages before exploring further. # Change Prepaid Units > Change the number of prepaid usage units in a subscription. ```py Python theme={null} lotus.change_prepaid_units( subscription_id='sub_a623349004cd4947aca1851c64aa6fbd', metric_id='metric_a47ac0bf', units=32, invoice_now=true ) ``` ```ts Typescript theme={null} await lotus.changePrepaidUnits({ subscription_id = "sub_a623349004cd4947aca1851c64aa6fbd", metric_id = "metric_a47ac0bf", units = 32, invoice_now = true, }); ``` In Lotus, you can define a certain number of units to be "prepaid" for a subscription. For example, if your business uses seats as a metric, you could define that your plan has 5 seats "prepaid" for each subscription. This means that the subscription will have 5 seats available for use, and you can add more seats as needed. This feature lets you have the benefits or charging flat fees in advance, while still metering the usage of the metric and allowing you to add more units as needed. This API is not currently available in our SDKs, but please contact us if you would like to use it as part of your workflow. If the change decreases the number of prepaid units, then the difference is awarded to the customer as a credit. If it icnreases, then you can choose between invoicing the difference immediately or adding it to the next invoice. ## OpenAPI ````yaml POST /api/subscriptions/{subscription_id}/components/{metric_id}/change_prepaid_units/ openapi: 3.0.3 info: title: Lotus API version: 0.9.3 description: >- Lotus is an open-core pricing and billing engine. We enable API companies to automate and optimize their custom usage-based pricing for any metric. servers: [] security: [] paths: /api/subscriptions/{subscription_id}/components/{metric_id}/change_prepaid_units/: post: tags: - api operationId: api_subscriptions_components_change_prepaid_units_create parameters: - in: path name: metric_id schema: type: string description: The ID of the metric to alter the prepaid usage for. required: true - in: path name: subscription_id schema: type: string description: The ID of the subscription which will have its plans switched. required: true requestBody: content: application/json: schema: $ref: '#/components/schemas/ChangePrepaidUnitsRequest' application/x-www-form-urlencoded: schema: $ref: '#/components/schemas/ChangePrepaidUnitsRequest' multipart/form-data: schema: $ref: '#/components/schemas/ChangePrepaidUnitsRequest' required: true responses: '200': content: application/json: schema: $ref: '#/components/schemas/SubscriptionRecord' description: '' security: - knoxTokenAuth: [] - OrganizationApiKeyAuth: [] TokenAuth: [] components: schemas: ChangePrepaidUnitsRequest: type: object properties: units: type: number format: double maximum: 10000000000 minimum: -10000000000 exclusiveMaximum: true exclusiveMinimum: true description: The new prepaid units for the customer. invoice_now: type: boolean default: true description: >- Whether or not to immediately invoice the customer for the change in prepaid units. required: - units SubscriptionRecord: type: object properties: subscription_id: type: string start_date: type: string format: date-time description: >- The time the subscription starts. This will be a string in yyyy-mm-dd HH:mm:ss format in UTC time. end_date: type: string format: date-time description: >- The time the subscription starts. This will be a string in yyyy-mm-dd HH:mm:ss format in UTC time. auto_renew: type: boolean description: Whether the subscription automatically renews. Defaults to true. is_new: type: boolean description: >- Whether this subscription came from a renewal or from a first-time. Defaults to true on creation. subscription_filters: type: array items: $ref: '#/components/schemas/SubscriptionFilter' customer: $ref: '#/components/schemas/LightweightCustomer' billing_plan: $ref: '#/components/schemas/LightweightPlanVersion' fully_billed: type: boolean readOnly: true addons: type: array items: $ref: '#/components/schemas/LightweightAddOnSubscriptionRecord' metadata: type: object additionalProperties: {} required: - addons - auto_renew - billing_plan - customer - end_date - fully_billed - is_new - metadata - start_date - subscription_filters - subscription_id SubscriptionFilter: type: object properties: value: type: string property_name: type: string description: 'The string name of the property to filter on. Example: ''product_id''' required: - property_name - value LightweightCustomer: type: object properties: customer_name: type: string readOnly: true nullable: true description: The display name of the customer email: type: string format: email readOnly: true nullable: true description: >- The primary email address of the customer, must be the same as the email address used to create the customer in the payment provider customer_id: type: string readOnly: true nullable: true description: >- The id provided when creating the customer, we suggest matching with your internal customer id in your backend required: - customer_id - customer_name - email LightweightPlanVersion: type: object properties: plan_name: type: string readOnly: true plan_id: type: string version_id: type: string readOnly: true version: oneOf: - type: integer - enum: - custom_version type: string readOnly: true required: - plan_id - plan_name - version - version_id LightweightAddOnSubscriptionRecord: type: object properties: addon_subscription_id: type: string start_date: type: string format: date-time readOnly: true description: >- The time the subscription starts. This will be a string in yyyy-mm-dd HH:mm:ss format in UTC time. end_date: type: string format: date-time readOnly: true description: >- The time the subscription starts. This will be a string in yyyy-mm-dd HH:mm:ss format in UTC time. addon: $ref: '#/components/schemas/LightweightAddOn' fully_billed: type: boolean readOnly: true required: - addon - addon_subscription_id - end_date - fully_billed - start_date LightweightAddOn: type: object properties: addon_name: type: string description: The name of the add-on plan. addon_id: type: string description: The ID of the add-on plan. addon_type: enum: - flat - usage_based type: string readOnly: true billing_frequency: enum: - one_time - recurring description: |- * `one_time` - one_time * `recurring` - recurring readOnly: true required: - addon_id - addon_name - addon_type - billing_frequency securitySchemes: knoxTokenAuth: type: apiKey in: header name: Authorization description: Token-based authentication with required prefix "Token" OrganizationApiKeyAuth: type: apiKey in: header name: X-API-KEY ````